1. Field of the Invention
This invention relates to cleaning machines and, more particularly, to a water extraction cleaning machine having a mixing valve adapted to create cleaning solution mixtures of variable constituent ratios.
2. Description of the Related Art
Water extraction cleaning machines have long been used for removing dirt from surfaces such as carpeting, upholstery, drapes, and the like. The known water extraction cleaning machines can be in the form of a canister type unit as seen in U.S. Pat. No. 5,237,720 to Blase et al. or an upright unit as seen in U.S. Pat. No. 5,500,977 to McAllise et al. and U.S. Pat. No. 4,559,665 to Fitzwater. The current water extraction cleaners can be difficult to use and often have limited adaptability for a variety of cleaning conditions. For example, none of the known water extraction cleaners provide means for quickly and efficiently varying the mixture ratio of detergent and water. In addition, none of the known upright water extraction cleaners provide means for automatic adjustment of the height of the roller-type agitation brush in response to changes on the surface being cleaned. Another problem inherent with the known water extraction cleaners is ease of use in filling and emptying the clean water tank and recovery tank. Finally, none of the known prior art water extraction cleaners incorporate means for quickly and easily converting between on-the-floor cleaning, and off-the-floor cleaning with an accessory hose and cleaning tool.
The Frohbieter U.S. Pat. No. 4,458,377 (issued Jul. 10, 1984) discloses a wet carpet cleaning apparatus wherein a fluid delivery system has a valve structure for delivering a detergent/water solution to nozzles for spraying the carpet. The valve is controllable so that it can be shut off, it can spray only water, or it can spray a low-detergent/water combination or a high-detergent/water combination. The valve includes an elongated hollow body with two spaced inlets, one for detergent and one for water. A slidable valve member has a series of o-rings which, in selected positions, block the flow of water through the valve, block the flow of detergent through the valve, or open the valve only for the flow of water, or open the valve for flow of a mixture of water and detergent. Water is supplied to the cleaning equipment through a hose connected to a domestic faucet.
U.S. Pat. No. 4,570,856 to Groth et al. (issued Feb. 18, 1986) describes an upright deep cleaning machine including means for mixing water and detergent concentrate. Water and detergent are drawn from their respective containers by vacuum suction generated by the vacuum motor, and separately enter a mixing valve with V-shaped passageways converging to mix the fluids prior to distribution onto the surface to be cleaned. A rocker arm is interconnected to a finger trigger for initially controlling the distribution of a predefined mixture of water and detergent onto the surface to be cleaned. Further articulation of the trigger results in varying the mixture to increase the level of detergent concentrate by restricting the water conduit upstream from the V-shaped mixing valve.
The Phillips et al. U.S. Pat. No. 3,940,826 (issued Mar. 2, 1976), shows a water extraction cleaner wherein pressurized water is supplied through a hose from an external source to a floor nozzle through a venturi-type injection valve, which includes a spring-biased ball in a valve chamber. A source of cleaning solution concentrate is connected to the injection valve. The flow of the cleaning solution concentrate to the injection valve is controlled by a metering valve with an adjusting knob on a handle. As long as the force of the water pressure is greater than the force of the spring biasing the ball, the ball is unseated to allow cleaning solution concentrate to be drawn into the stream of pressurized water.